The present invention relates to a gripper device, which is designed so as to be movable along a movement path, and to serve the purpose of grasping and holding a workpiece, and of moving the workpiece along the movement path, in accordance with the preamble of the main claim. The present invention also relates to the utilisation of such a gripper device.
Generic gripper devices are generally of known art in the technical fields of robotics, factory automation and material handling. With the purpose of gripping a wide variety of workpieces for movement purposes at a first position on a movement path, and then passing them on to a different second position of the movement path, generic gripper devices are typically implemented as operative elements in terms of arms or jaws designed for gripping purposes, which, in reaction to a (typically pneumatic or electromagnetic) drive enter into an operative pairing with the workpiece (effecting, for example a force fit and/or form fit with the workpiece) and then by virtue of movement of the gripper device also enable the (accompanying) movement of the workpiece.
Depending upon the purpose of movement, that is to say, of conveying, and the type, contour, or surface configuration of the workpiece, one of the gripping principles of known art is of advantage, wherein, in addition to the properties of the workpiece other constraints play a role, such as cycle times (for the gripping action, and/or the transportation movement), numbers of cycles, that is to say, the service lives that must be guaranteed, or other environmental conditions (and also, for example, the stresses caused by moisture, cold, or dust).
It is also of known art to require, in principle, the use from the prior art of an actuator system for generic gripping purposes implemented in terms of a magnetic shapememory alloy material (also referred to as MSM=magnetic shape-memory); in another manner of known art, an actuator is employed for the purpose of gripping the workpiece, which can expand in response to the energising of a coil, in particular a coil appropriately surrounding an actuator crystal, wherein, compared with gripper systems implemented in terms of pneumatics or electric motors for example, the MSM material shows advantages, for example, in terms of reaction times, and the speed of the drive movement.
For all generic actuator means and associated drive and actuation principles of presupposed known art it is nevertheless a common factor that the actuator means must be provided with complex peripheral units together with supply lines; thus these are, for example, the fluid (pressure) supply lines of pneumatic systems, and the electrical supply cables, together with the coils that have been cited, in the case of systems based on electric motors and MSM materials. However, such additional infrastructures of lines and cables are subject to loads promoting high wear, in particular in cases of high accelerations, large numbers of movement cycles, and/or in cases of systems deployed in stressful environments, which loads often limit the effective service lives of systems that are implemented in this manner, and/or determine maintenance and overhaul cycles, with corresponding expenditure of time and costs, which result in a need for improvement, in particular in industrial conveyor systems, logistics and production environments.
Moreover the generic provision of the infrastructure of lines, cables and drives as described on gripper devices of known art causes moving components, such as, for example, the arms or jaws forming the first and second contact sections, to be additionally loaded by the masses that are being moved, with the result that the dynamic behaviour of the gripper device is impaired. Thus, for example, the potential (switching) speed advantages of a magnetic MSM actuator are thereby in part in turn negatively affected by the fact that in the context of the overall system the coil means required for the application of a magnetic field onto the MSM crystal, together with the supply lines, increase the mechanical inertia of the overall system. The same is true for electromotive or pneumatic actuator means, whose ability to move (and to accelerate) is impaired or limited in the same manner by the infrastructure of supply lines and cables as discussed.